Patent GB-656666-A (GB)
Title: Improvements in or relating to driving mechanism for cinematographic apparatus
Inventor: BOWLER VALENTINE MARCUS
IPC: G03B21/43
Filed: 1948-06-11
Abstract: 656,666. Kinematograph apparatus. KODAK, Ltd. June 11, 1948, No. 15809. [Class 97 (i)] [Also in Group XXIV] A driving mechanism for the take-up spindle comprises a belt-driven pulley slidably and rotatably mounted on the spindle, co-operating clutch elements on the spindle and pulley, cam means for automatically displacing the pulley along the spindle in one direction, upon rotation of the pulley for normal running, to engage the clutch elements and drive the spindle, and spring means for automatically displacing the pulley along the spindle in the opposite direction, during reverse rotation of the spindle independently of the pulley drive, to disconnect the clutch elements and to permit the spindle to idle, for example, for rewind or reverse running of the film. In the form shown, a spool spindle 1 is carried at the end of an arm 2. The pulley 4 is frictionally driven, as by a belt, and is mounted loose on the spindle, but when driven in the direction of the arrow is moved axially outward so that an outwardly projecting pin 6 engages with one of the pins 5 carried on a spring blade 21 and projecting inwardly through slots 25 in a disc 22, the blade and the disc being secured at the end of the shaft and retaining a spring 7 which produces an inward force on the pulley. The outward axial movement of the pulley is produced by ratchet-like cam portions 10 on a ring 11 carried on a bearing 12 on the arm 2. The rotation of the ring is limited by the inwardly projecting end of a pin 13 engaging a flat surface 14 formed on the bearing 12. The cams 10 can engage slots 9 in the hub 8 on the pulley and the slots 16 in a member 15 concentric with the hub. The end faces of the cams prevent reverse rotation of the pulley. When the pulley is rotated in the direction of the arrow the edges of the slots 9 in its hub ride up the sloping faces of the cams 10 which then ride, with continued rotation of the pulley, on the end face of the hub, and on the faces 17 of the member 15. The cams 10 are then retained on the faces 17 since the member 15 has been partially rotated by friction within the limits permitted by the ends 18, at one of the slots 16, of an upstanding wall surrounding , the surfaces 17, an outwardly projecting portion of the pin 13 being engaged between these ends. If now a reverse rotation of the spindle is produced by pull on the film during rewinding the engagement between the pin 6 and one of the pins 5 turns the pulley backwards until the cams 10 re-engage the slots 9 and the pins are disengaged. The backward rotation of the pulley produces an increased tension in one reach of the driving belt and provision is made that this tension does not, after the pulley is disengaged from the spindle tend to rotate the pulley forwards to re-engage it. This provision is the limited movement of the ring 11 and a spring 19 between the pin 13 therein and a pin 20 on the arm 2 urging the ring in the forward direction of spindle rotation. The upstanding wall of the member-15 surrounding the surfaces 17 is recessed at 30 to clear the pin 13.